1. Technical Field
An aspect of the present invention relates to an image forming apparatus which is capable of forming images on either side of a recording sheet.
2. Related Art
A printer which is capable of forming images on either side of a sheet of recording medium (e.g., paper) is known. When images are formed on both sides of the sheets (i.e., double-face printing), the printer may form images firstly on a same side of N sheets (N being a positive integer) continuously in a batch and thereafter on the other side of M sheets (M being a positive integer smaller than or equal to N). Thus, the double-face printing on both sides of the sheets can be completed in a shorter period of time than printing one side and the other side alternately. Such a shortened double-face printing operation, in which a plurality of sheets can reside in a sheet-feeding path at a same time, may be called quick double-face printing. For example, when images are formed on each side of 5 sheets of paper (i.e., 1-10 pages), the images may be formed on a second (even-numbered) page, a fourth (even-numbered) page, a first (odd-numbered) page, a sixth (even-numbered) page, a third (odd-numbered) page, an eighth (even-numbered) page, a fifth (odd-numbered) page, a tenth (even-numbered) page, a seventh (odd-numbered) page, and a ninth (odd-numbered) page in the order mentioned. For another example, images may be formed on first, third, fifth, second, seventh, fourth, ninth, sixth, eighth, and tenth pages in the order mentioned.